Contenttype: text/html
Man page of Bignum
Bignum
Section: User Contributed Perl Documentation (3pm)
Updated: 20070520
Index
Return to Main Contents
NAME
Crypt::OpenSSL::Bignum  OpenSSL's multiprecision integer arithmetic
SYNOPSIS
use Crypt::OpenSSL::Bignum;
my $bn = Crypt::OpenSSL::Bignum>new_from_decimal( "1000" );
# or
my $bn = Crypt::OpenSSL::Bignum>new_from_word( 1000 );
# or
my $bn = Crypt::OpenSSL::Bignum>new_from_hex("0x3e8");
# or
my $bn = Crypt::OpenSSL::Bignum>new_from_bin(pack( "C*", 3, 232 ))
use Crypt::OpenSSL::Bignum::CTX;
sub print_factorial
{
my( $n ) = @_;
my $fac = Crypt::OpenSSL::Bignum>one();
my $ctx = Crypt::OpenSSL::Bignum::CTX>new();
foreach my $i (1 .. $n)
{
$fac>mul( Crypt::OpenSSL::Bignum>new_from_word( $i ), $ctx, $fac );
}
print "$n factorial is ", $fac>to_decimal(), "\n";
}
DESCRIPTION
Crypt::OpenSSL::Bignum provides access to OpenSSL multiprecision
integer arithmetic libraries. Presently, many though not all of the
arithmetic operations that OpenSSL provides are exposed to perl. In
addition, this module can be used to provide access to bignum values
produced by other OpenSSL modules, such as key parameters from
Crypt::OpenSSL::RSA.
NOTE: Many of the methods in this package can croak, so use eval, or
Error.pm's try/catch mechanism to capture errors.
Class Methods
 new_from_word

Create a new Crypt::OpenSSL::Bignum object whose value will be the
word given. Note that numbers represneted by objects created using
this method are necessarily between 0 and 2^32  1.
 new_from_decimal

Create a new Crypt::OpenSSL::Bignum object whose value is specified by
the given decimal representation.
 new_from_hex

Create a new Crypt::OpenSSL::Bignum object whose value is specified by
the given hexidecimal representation.
 new_from_bin

Create a new Crypt::OpenSSL::Bignum object whose value is specified by
the given packed binary string. Note that objects created using this
method are necessarily nonnegative.
 zero

Returns a new Crypt::OpenSSL::Bignum object representing 0
 one

Returns a new Crypt::OpenSSL::Bignum object representing 1
 bless_pointer

Given a pointer to a OpenSSL BIGNUM object in memory, construct and
return Crypt::OpenSSL::Bignum object around this. Note that the
underlying BIGNUM object will be destroyed (via BN_clear_free(3ssl))
when the returned Crypt::OpenSSL::Bignum object is no longer
referenced, so the pointer passed to this method should only be
referenced via the returned perl object after calling bless_pointer.
This method is intended only for use by XSUB writers writing code that
interfaces with OpenSSL library methods, and who wish to be able to
return a BIGNUM structure to perl as a Crypt::OpenSSL::Bignum object.
Instance Methods
 to_decimal

Return a decimal string representation of this object.
 to_hex

Return a hexidecimal string representation of this object.
 to_bin

Return a packed binary string representation of this object. Note
that sign is ignored, so that to bin called on a
Crypt::OpenSSL::Bignum object representing a negative number returns
the same value as it would called on an object representing that
number's absolute value.
 get_word

Return a scalar integer representation of this object, if it can be
represented as an unsigned long.
 is_zero

Returns true of this object represents 0.
 is_one

Returns true of this object represents 1.
 is_odd

Returns true of this object represents an odd number.
 copy

Returns a copy of this object.
 add

This method returns the sum of this object and the first argument. If
only one argument is passed, a new Crypt::OpenSSL::Bignum object is
created for the return value; otherwise, the value of second argument
is set to the result and returned.
 sub

This method returns the difference of this object and the first
argument. If only one argument is passed, a new
Crypt::OpenSSL::Bignum object is created for the return value;
otherwise, the value of second argument is set to the result and
returned.
 mul

This method returns the product of this object and the first argument,
using the second argument, a Crypt::OpenSSL::Bignum::CTX object, as a
scratchpad. If only two arguments are passed, a new
Crypt::OpenSSL::Bignum object is created for the return value;
otherwise, the value of third argument is set to the result and
returned.
 div

This method returns a list consisting of quotient and the remainder
obtained by dividing this object by the first argument, using the
second argument, a Crypt::OpenSSL::Bignum::CTX object, as a
scratchpad. If only two arguments are passed, new
Crypt::OpenSSL::Bignum objects is created for both return values. If
a third argument is passed, otherwise, the value of third argument is
set to the quotient. If a fourth argument is passed, the value of the
fourth argument is set to the remainder.
 exp

This method returns the product of this object exponeniated by the
first argument, using the second argument, a
Crypt::OpenSSL::Bignum::CTX object, as a scratchpad.
 mod_exp

This method returns the product of this object exponeniated by the
first argument, modulo the second argument, using the third argument, a
Crypt::OpenSSL::Bignum::CTX object, as a scratchpad.
 pointer_copy

This method is intended only for use by XSUB writers wanting to have
access to the underlying BIGNUM structure referenced by a
Crypt::OpenSSL::Bignum perl object so that they can pass them to other
routines in the OpenSSL library. It returns a perl scalar whose IV
can be cast to a BIGNUM* value. This can then be passed to an XSUB
which can work with the BIGNUM directly. Note that the BIGNUM object
pointed to will be a copy of the BIGNUM object wrapped by the
instance; it is thus the responsiblity of the client to free space
allocated by this BIGNUM object if and when it is done with it. See
also bless_pointer.
AUTHOR
Ian Robertson, [email protected]
SEE ALSO
perl, bn(3ssl)
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 Class Methods

 Instance Methods

 AUTHOR

 SEE ALSO

This document was created by
man2html,
using the manual pages.
Time: 04:14:11 GMT, September 24, 2010